Eugene conrady



(No Model.)

E. GONRADY. LATHE.

MTN 55555: INVENT'CJR;

s No nu, u4 c.

Nrrnn STATES PATENT OFFICE.

EUGENE CONRADY, OF KEIGI-ILEY, ENGLAND.

LATHE.

SPECIFICATION forming part of Letters Patent No. 475,671, dated May `24, 1892. Application filed August 8, 1891. Serial No. 402,116. (No model.) 4

To @ZZ whom t may concern:

Be it known that I, EUGENE CONRADY, of

Keighley, in the county of York, England, have invented certain new and useful Improvements in Lathes, of which the following is a specification.

This invention relates to lathes; and it has forits object to provide a lathe-hed of such form as will do away with the necessity of a number of true and parallel surfaces on the same and on the head-stock, tail-stock, toolcarriage, dto., sliding thereon.

The invention also has for its object to provide a lathe-bed of a form which will neutralize any lateral play or side shake of the slid ing parts above mentioned upon the same and will preventsaid side shake from making any variation in the position of the tool with respect to the center line or axis of the spindle of the lathe.

The invention consists in a lathe-bed having a bearing-surface for the sliding parts, such as the head-stock, tail-stock, and toolcarriage, said parts each having a bearing- Surface corresponding to the bearing-surface of the bed, a cross-section of the lathe-bed, showing the bearing-surface thereof formed on a curve which is an arc of acircle, of which the center is the axial line of the spindle thereof, all of which I will now proceed to describe and claim.

In the accompanying drawings, forming a a part of this specification, Figure l represents a cross-section of a lathe-bed embodyingr my invention. Fig. 2 represents a similar view showing a slightly different form of lathe-bed. Fig. 3 represents a similar view showing another slight change in the form of the lathe-bed. Fig. 4 represents a similar View showing a modification. Fig. 5 represents a front elevation of a lathe, showingthe general arrangement of the parts.

The same letters of reference indica te the same parts in all the figures.

In lathes nowin common use the lathe-bed is made with a level upper surface and with two or more inclined surfaces, or with a level upper surface with guides or ways projecting upwardly therefrom, on which the sliding` parts move and to which they are accurately fitted. It is essential to the correct Working of the lathe that each of these surfaces should be perfectly true and that they should all be true to each other, for if they be not true, and

the moving parts do not lit them with thel greatest accuracy, said parts will have a certain amount of lateral play or side shake and the centers or the tool will shift, thus rendering accurate work impossible. I have overcome this diflicnlty and have made the accu- 6o racy of a lathe to depend on the truth of one bearingsurface only by means of the invention which I will now proceed to describe.

In carrying out my invention Iconstruct a lathe-bed a with its upper surface curved in cross-section, the curve of said upper surface being an arc of a circle, of which the center is the axial line of the spindle.

b represents the head-stock of the lathe.

In the form of my invention shown in Fig. l I show the bed a divided by a groove or slot, having the side faces a a. The head-stock b is provided with a projection b', which enters the said slot and prevents said head-stock from moving laterally too far for convenience in practical use. It will be observed, howeven if the head-stock is allowed a comparatively great amount of lateral play this movement will not affect or shift the center of rotation of the spindle or of the work held by the lathe, it being readily understood that said side play takes place on a curved bearing-surface, the curve of which is an arc of a circle of which said center of rotation is the central point, so that no movement on the line of said arc can change the position of the center.

IniFig. 2 I have shown the bed a provided with an upward projection d2 and the headstock Z) provided with a slot or groove b2 to receive the same, the functions of said projection and slot being the saine as those of the slot and projection shown in Fig. l.

In Fig. 3 I show another form of the invention, in which the head-stock l) overlaps at the front and back the bed a, and has two downward projections b3 o3 lying alongside of the hack and front edges c3 a3 of the bed a. These projections b3, bearing on the edges of the bed, serve the saine purpose as the slots and projections shown in the two forms first described, as will be readily seen.

In cases where the strain is such as to tend IOO to lift the sliding parts off the lathe-bed I provide the modified form shown in Fig. 4. In this form the curved bearing-surface of the lathe-bed is on the und er side of the same and is of course convex. The said convex under side of the lathe-bed is also curved in the arc of a circle of which the axis of the lathespindle is the center.

The head-stock b is provided with anges b4 b4, which fit around the edges and under the su rfaces a4 a4 of the bed.

In speaking of the head-stock b in describing the various forms of my invention above it will be obvious that the tail-stock and toolcarriage are constructed similarly and that the head-stock stands for a type of the sliding parts ot' the lathe whatever they may be called.

It will be readily understood that any part of a sliding part of a lathe thus constructed will always maintain the same dist-ance from the centerline of the lathe, and consequently that a cutting-tool attached to the tool-carriage or slide-rest of a lathe of this construction will turn a piece of work revolving between the lathe-centers perfectly true and parallel, however much lateral play the toolcarriage may have.

rlhe general arrangement of a simple lathe, according to my invention,is shown in Fig. 5, in which the head-stock b and tailstock c are shown fixed to the bed a in the usual Way by bolt and nut and the saddle d for the sliderest held down to the bed by a fiat spring e of suitable strength with anti-friction rollers ff at its ends.

All appliances used on common lathessuch, for instance, as automatic feed and screw-cutting attachments-can, of course, be fitted to lathes of my construction.

The term lathe in this specification is intended to comprise, first, all kinds of common lathes in which the Work revolves while the tool stands still, including those for special Work-as, for instance, screw-making lathes, turret-lathes, and similar machines; second, boring-machines, such as are used for boring out the cylinders of steam-engines and for similar work, the characteristic of this second kind of lathes being that the Work isheld stationary on a table While the cutting-tool revolves.

I do not desire to limit myself to the specific formsof lathe-bedherein shown and described, as the same may be varied in many ways Without departing from the spirit of my invention, the essential feature of my invention being the curved bearing-surface of the bed which is an are of a circle of which the center of rotation of the spindle is the center.

I claim- .1. ln a lathe, the improved bed havinga guiding or bearing surface which is curved in cross-section, the curve of said surface being an arc of a circle of which the center is the axial line of the spindle thereof, as set forth.

2. In a lathe, the combination of a bed having a guiding or bearing surface which is curved in cross-section,the curve of said surface being an arc of a circle of Which the center is the axial line of the spindle thereof, and

EUGENE CONRADY.

Witnesses:

HORACE W. S'rANsFELD,

,Merchant Bradford. WVM. TEALE KIRK,

Cashier, Bradford. 

